Absorbent articles such as diapers, training pants, incontinence products, feminine hygiene products, swim undergarments, and the like conventionally include a liquid permeable body-side liner, a liquid impermeable outer cover, and an absorbent core. The absorbent core is typically located in between the outer cover and the liner for taking in and retaining liquids (e.g., urine) exuded by the wearer.
The absorbent core can be made of, for instance, superabsorbent particles. Many absorbent articles, especially those sold under the tradename HUGGIES™ by the Kimberly-Clark Corporation, are so efficient at absorbing liquids that it is sometimes difficult to tell whether or not the absorbent article has been insulted with a body fluid.
Accordingly, various types of electronic moisture or wetness indicators have been suggested for use in absorbent articles. The wetness indicators may include alarm devices that are designed to assist parents or attendants identify a wet diaper condition early on. The devices can produce an audible, tactile, electromagnetic or visual signal.
In some embodiments, for instance, conductive threads or foils have been placed in the absorbent articles that extend from the front of the article to the back of the article. The conductive materials serve as conductive leads for a signaling device and form an open circuit in the article that can be closed when a body fluid, such as urine, closes the circuit.
Incorporating conductive leads into absorbent articles, however, has caused various problems. For example, absorbent articles are typically mass produced on very fast moving machinery. Incorporating conductive leads into an absorbent article at conventional machine speeds has been problematic.
In addition, packaged absorbent articles are typically fed through a metal detector to ensure that there are no foreign objects contained in the package. If the conductive leads are made from or contain a metal, the metal detector may be activated registering a false positive. The incorporation of metallic materials into absorbent articles can also cause problems for those wearing the garments when attempting to pass through security gates that include metal detectors.
In view of the above, a need currently exists for a signaling system for an absorbent article that does not require conductive elements containing metal or other devices to be inserted into the interior of the article.